Painful diabetic peripheral neuropathy of the feet: integrating prescription-strength capsaicin into office procedures

Prescription-strength (8%) capsaicin topical system is a US FDA-approved treatment for painful diabetic peripheral neuropathy of the feet. A 30 min application of the capsaicin 8% topical system can provide sustained (up to 3 months) local pain relief by desensitizing and reducing TRPV1-expressing cutaneous fibers. Capsaicin is not absorbed systemically; despite associated application-site discomfort, capsaicin 8% topical system is well tolerated, with no known drug interactions or contraindications, and could offer clinical advantages over oral options. Capsaicin 8% topical system are not for patient self-administration and require incorporation into office procedures, with the added benefit of treatment compliance. This article reviews existing literature and provides comprehensive, practical information regarding the integration of capsaicin 8% topical systems into office procedures.

Perioperative Use of Ketamine

PURPOSE OF REVIEW

Postoperative pain continues to be one of the most common challenges following surgeries. Multimodal analgesia has been of particular focus as non-opioid alternatives have been encouraged due to concerns of the opioid epidemic. Ketamine has been an especially useful adjunct in multimodal pain regimens within the past few decades. This article highlights the current use and advances surrounding the perioperative use of ketamine.

RECENT FINDINGS

Ketamine has antidepressive effects at subanesthetic doses. Intraoperative ketamine may be beneficial in reducing postoperative depression. Additionally, newer studies are exploring whether ketamine can be useful in reducing postoperative sleep disturbances. Ketamine continues to be a great tool in perioperative pain control, especially during an opioid epidemic. As its use continues to expand and gain more popularity in the perioperative period, more research could shed light on the additional nonanalgesic benefits of ketamine use.

A Review of the Paravertebral Block: Benefits and Complications

PURPOSE OF REVIEW

Paravertebral nerve blocks (PVB) have experienced a surge over the past 2 decades as improved access to ultrasound has increased ease of performance. The purpose of this review is to identify recent findings with regard to PVB's uses, including benefits, risks, and recommendations.

RECENT FINDINGS

PVB is reported as an effective method of analgesia both in intraoperative and postoperative applications, with novel applications showing its potential to replace general anesthesia for certain procedures. The use of PVB as a method of analgesia postoperatively has shown lower opioid usage and faster PACU discharge, when compared to alternative approaches like the intercostal nerve block, erector spinae plane block, pectoralis II block, and patient-controlled analgesia. Thoracic epidural analgesia and a serratus anterior plane block are comparable to PVB and can be used as alternatives. The incidence of adverse events is consistently reported to be very low with few new risks being identified as the use of PVB expands. While there are worthwhile alternatives to PVB, it is an excellent option to consider, particularly for higher-risk patients. For patients undergoing thoracic or breast surgery, PVB can improve opioid usage and shorten the length of stay leading to an overall positive impact on patient recovery and satisfaction. More research is needed to further expand novel applications.

Contrast Spread After Erector Spinae Plane Block at the Fourth Lumbar Vertebrae: A Cadaveric Study

INTRODUCTION

In recent years, the erector spinae plane block (ESPB) has seen widespread use to treat acute and chronic pain in the regions of the thoracic spine. While limited data suggest its increasing utilization for pain management distal to the thoracic, abdomen and trunk, the anesthetic spread and analgesic mechanism of ESPB at the level of the lumbar spine has not been fully described or understood.

METHODS

This is an observational anatomic cadaveric study to assess the distribution of solution following an ESPB block performed at the fourth lumbar vertebrae (L4) using ultrasound guidance to evaluate the spread of a 20 ml solution consisting of local anesthetic and methylene blue. The study was performed in an anatomy lab in a large academic medical center. Following injection of local anesthetic with contrast dye, cadaveric dissection was performed to better understand the extent of contrast dye and to determine the degree of staining to further predict analgesic potential. We reviewed the findings of other ESPB cadaveric studies currently available for comparison.

RESULTS

Following cadaveric dissection in an anatomy lab, the contrast dye was observed in the ESP space, and staining was found most cranially at L2 and extending caudally underneath the sacrum. Evaluating the depth of its spread, we found it to be confined to the posterior compartment of the spine sparing the nerve roots bilaterally, which is consistent with the only other cadaveric study of ESPB performed at L4.

CONCLUSION

Our results demonstrate the clinical utility of lumbar ESPB where posterior confinement of local anesthesia is preferred. However, further investigation is needed to determine the efficacy of ESPB in lower extremity analgesia which is predicated on ventral nerve root involvement.

Platelet-Rich Plasma in the Treatment of Facet Mediated Low Back Pain: A Comprehensive Review

Background

Facet-mediated pain is a major cause of low back pain and as a result, is a significant cause of morbidity, including disability and reduced functionality.

Setting

The present investigation involved a PubMed literature review between June 1, and 2021-January 1, 2022.

Methods

We systematically reviewed was carried Pubmed using the search terms "platelet-rich plasma", "inflammatory mediators", "facet arthropathy", "axial back pain", and "leukoreduction". Data extraction and quality assessment were performed by 3 independent reviewers. Out of the studies analyzed 2 were retrospective, while 1 was a prospective study.

Results

PRP injections for facet mediated or modulated pain are an alternative to conventional pharmacotherapies and interventional injections/radiofrequency. There are limited numbers of studies in world literature at present.

Limitations

Small number of articles in the world literature and small numbers of patients in those published studies.

Conclusions

At present, there are limited studies in the literature; however, larger well-designed studies are warranted to precisely understand efficacy, potential side effects and best practice techniques for PRP injections for facet mediated or modulated pain.

Patients on Buprenorphine Formulations Undergoing Surgery

PURPOSE OF REVIEW

To review the pharmacology of buprenorphine, the evolution of buprenorphine dosing recommendations, and the current literature regarding its recommendations for the perioperative period.

RECENT FINDINGS

There is a consensus that for all surgeries, buprenorphine should be continued throughout the perioperative period. If the surgery is a minimal to mild pain surgery, no dose adjustment is needed. There is no clear consensus regarding moderate to severe pain. With all surgeries, multimodal analgesia should be utilized, with regional anesthesia when possible. Patients taking buprenorphine should continue their buprenorphine perioperatively; whether to decrease or maintain dosing is up for debate. Multimodal analgesia should also be used throughout the perioperative period, and communication between the patient and all provider teams is of the utmost importance to provide adequate analgesia during the perioperative period, as well as to arrange safe analgesia upon discharge.

Radiofrequency Ablation for the Knee Joint: A Survey by the American Society of Pain and Neuroscience

Background

Genicular nerve radiofrequency ablation (RFA) is an effective, minimally invasive procedure often used to treat patients with intractable knee pain secondary to knee osteoarthritis and failed knee replacements. The prevalence of knee pain in adults has been estimated to be as high as 40% and is continuously increasing with an aging population. Over the past two decades, proceduralists have adopted variations in patient preparation, procedural steps, and post-operative care for genicular nerve RFA procedures. A survey was dispensed via the American Society of Pain and Neuroscience (ASPN) to gain a popular assessment of common practices for genicular nerve RFA.

Methods

A 29 question survey was dispensed via SurveyMonkey to all members of ASPN. Members were able to respond to the survey a single time and were unable to make changes to their responses once the survey was submitted. After responses were compiled, each question was assessed in order to determine common practices for genicular nerve RFA.

Results

A total of 378 proceduralists responded to the survey. There was high consensus with the three most commonly targeted nerves. The inferomedial, superomedial, and superolateral genicular branches were treated by 95–96% of respondents, while other targets were less commonly treated. There remains some debate among proceduralists regarding the need for a second diagnostic nerve block and the type of steroid used for diagnostic nerve blocks.

Conclusion

Pain physicians use a wide variety of methods to perform genicular nerve ablations. The data offered by the survey show that there is no standardized protocol when it comes to treating knee pain via genicular nerve block and ablation and highlights controversies among proceduralists that ought to serve as the targets of future clinical research aimed at establishing a standardized protocol.

Transcutaneous Electrical Nerve Stimulation as a Treatment for Neuropathic Cough: A Tolerability and Feasibility Study

Transcutaneous electrical nerve stimulation (TENS) is a form of electroanalgesia used for neuropathic pain disorders. Refractory chronic cough, or “neuropathic cough,” may be physiologically similar to other neuropathic pain conditions. This study explored the tolerability and feasibility of using TENS as a treatment for neuropathic cough. Laryngeal TENS was administered to five subjects with neuropathic cough. One electrode was placed over the lateral thyrohyoid membrane, and a second over the cricothyroid space. A frequency of 120 Hz was applied for 30 min. Participants rated symptoms pre-, during, and post-TENS treatment using a Likert scale. Laryngeal TENS was well tolerated by all subjects. Adverse effects included brief neck discomfort when increasing TENS intensity and an event of mild post-treatment hoarseness. The self-reported scores trended toward a reduction in symptom severity during and after treatment. Controlled trials using this method would elucidate the use of TENS for treatment of patients suffering from chronic cough.

Transversus Abdominis Plane Block for Laparoscopic Hysterectomy Pain: A Meta-Analysis

Objective:

Review the analgesic effect of the transversus abdominis plane (TAP) block and its impact on postoperative pain scores and opioid usage for patients undergoing laparoscopic and robotic hysterectomies.

Methods:

Systematic review with meta-analysis of randomized controlled trials that compared the effect of TAP block to either placebo or no block on narcotic use (in morphine equivalent units [MEq]) and pain (per visual analog scale) within 24] h after a laparoscopic or robotic hysterectomy for benign or malignant indications. Searches were conducted in PubMed and Embase through May 31, 2019.

Results:

Nine randomized controlled trials met eligibility criteria; 7 evaluated laparoscopic hysterectomy and 2 robotic hysterectomy. A total of 688 subjects were included (559 laparoscopic hysterectomy, 129 robotic hysterectomy). Opioid consumption was similar in the first 24] h postoperative with or without TAP block (−0.8 MEq; 95% CI, −2.9, 1.3; 8 TAP arms; N] = 395). Pain scores (visual analog scale) were also similar with or without TAP block (−0.01 U; 95% CI, −0.34, 0.32; 10 TAP arms; N] = 636). Neither meta-analysis showed statistical heterogeneity across studies.

Conclusions:

The evidence does not support a benefit of TAP block to reduce pain or opioid use for patients receiving laparoscopic or robotic hysterectomies.

Considerations for Epidural Blood Patch and Other Postdural Puncture Headache Treatments in Patients with COVID-19

BACKGROUND

A primary concern in the use of EBP in these patients is the possibility of seeding the virus in the CNS. Another important concern is related to the known hypercoagulable state in COVID-19 positive patients and associated organ dysfunction that may alter the metabolism of anticoagulants. The safety of the providers performing the EBP, the position of the patient and choices for image guidance (blind, fluoroscopic) are also key considerations to review. It is also important to explore the current state of knowledge about using allogenic instead of autologous blood as well as emerging techniques to eliminate the coronavirus from the blood.

OBJECTIVES

In this article we pose the questions of how to manage PDPH in the COVID-19 positive patient and more specifically, the use of epidural blood patch (EBP).

METHODS

Literature review.

RESULTS

EBP is usually considered after the failure of conservative and pharmacological treatments. Because of the additional risks of EBP in COVID-19 patients it is important to also consider less traditional pharmacological treatments such as theophylinnes and cosyntropin that may offer some additional benefit for COVID-19 patient. Finally, other interventions other than EBP should also be considered including occipital nerve blocks, sphenopalatine ganglion blocks (infratemporal or transnasal).

LIMITATIONS

A narrative review with paucity of literature.

CONCLUSION

Going forward, an effective treatment for COVID-19 or a safe vaccine and a deeper understanding of the pathophysiology of the virus will certainly change the risk calculus involved in performing an EBP in a COVID-19 patient.

Anesthesia residency training in regional anesthesiology and acute pain medicine: a competency-based model curriculum

The Accreditation Council for Graduate Medical Education has shifted to competency-based medical education. This educational framework requires the description of educational outcomes based on the knowledge, skills and behaviors expected of competent trainees. It also requires an assessment program to provide formative feedback to trainees as they progress to competency in each outcome. Critical to the success of a curriculum is its practical implementation. This article describes the development of model curricula for anesthesiology residency training in regional anesthesia and acute pain medicine (core and advanced) using a competency-based framework. We further describe how the curricula were distributed through a shared web-based platform and mobile application.

Preoperative frailty assessment combined with prehabilitation and nutrition strategies: Emerging concepts and clinical outcomes

Important elements of the preoperative assessment that should be addressed for the older adult population include frailty, comorbidities, nutritional status, cognition, and medications. Frailty has emerged as a plausible predictor of adverse outcomes after surgery. It is present in older patients and is characterized by multisystem physiologic decline, increased vulnerability to stressors, and adverse clinical outcomes. Preoperative preparation may include a prehabilitation program, which aims to address nutritional insufficiencies, modify chronic polypharmacy, and enhance physical and respiratory conditions prior to hospital admission. Special considerations are taken for particularly high-risk patients, where the approach to prehabilitation can address specific, individual risk factors. Identifying patients who are nutritionally deficient allows practitioners to intervene preoperatively to optimize their nutritional status, and different strategies are available, such as immunonutrition. Previous studies have shown an association between increased frailty and the risk of postoperative complications, morbidity, hospital length of stay, and 30-day and long-term mortality following general surgical procedures. Evidence from numerous studies suggests a potential benefit of including a standard assessment of frailty as part of the preoperative workup of older adult patients. Studies addressing validated frailty assessments and the quantification of their predictive capabilities in various surgeries are warranted.

Needle-Through-Needle Technique in Lumbar Interlaminar Epidural Steroid Injection: A Case Report

When performing lumbar epidural steroid injection on obese patients, needle placement can be challenging due to the difficulty in estimating the appropriate needle length to utilize. Often times, the standard 3.5-inch Tuohy needle is too short to reach its target. In our case report, a needle-through-needle technique was attempted in a lumbar interlaminar epidural steroid injection procedure after the initial needle fell short of the epidural space. To avoid removing the initial needle and restarting the procedure using a longer needle, a 20-gauge 6-inch Tuohy needle was inserted into the 17-gauge 3.5-inch Tuohy needle, successfully reaching the epidural space. This technique can facilitate quicker needle placement by avoiding the need for restarting the procedure with a longer needle. Thus, procedural time and radiation exposure may be decreased, as may patient discomfort from repeat needle insertions.

Incidence of vocal cord paresis following ultrasound-guided interscalene nerve block: An observational cohort study

BACKGROUND

Interscalene brachial plexus block (IBPB) has become a standard practice for perioperative analgesia for shoulder procedures. However, several side effects may occur owing to its anatomic location. We have chosen to evaluate vocal cord paresis and dysphonia following interscalene blocks.

METHODS

After IRB approval, eight patients undergoing arthroscopic shoulder procedures were recruited into this prospective cohort study. Following informed consent, vocal cords were assessed by standardized fiberoptic evaluation. Subsequently, IBPB was performed under ultrasound (US) guidance. Patients were re-evaluated for vocal cord changes by a repeat fiberoptic assessment one hour following IBPB. Our primary outcome measure was incidence of vocal cord immobility.

RESULTS

No patients had diminished vocal cord motion, dysphonia, or dysphagia.

CONCLUSIONS

Although larger studies are required to determine the true incidence of vocal cord paresis following US-guided IBPB, our results suggest that incidence of unwanted nerve blockade other than brachial plexus is much lower than that previously described.

A Randomized Comparison of Pain Control and Functional Mobility between Proximal and Distal Adductor Canal Blocks for Total Knee Replacement

Background:

Adductor canal blocks (ACBs) have become a popular technique for postoperative pain control in total knee arthroplasty patients. Proximal and distal ACB have been compared previously, but important postoperative outcomes have yet to be assessed.

Aims:

The primary objective of this study is to compare postoperative analgesia between proximal and distal ACB. Secondary outcomes include functional mobility, length of stay (LOS), and adverse events.

Settings and Design:

This study was a single-center, assessor-blinded, randomized trial.

Subjects and Methods:

Fifty-seven patients were randomly assigned to receive a proximal (n = 28) or distal (n = 29) ACB. A 20 mL bolus of 5 mg/mL ropivacaine was injected at the respective location followed by 2.0 mg/mL ropivacaine infusion for 24 h.

Statistical Analysis:

The primary outcome was intra- and postoperative 24-h opioid consumption in intravenous (IV) morphine equivalents. Secondary outcomes include percentage change in timed “Up and Go” (TUG) times, LOS, and average postoperative pain scores. Continuous variables were compared using Student's t-test.

Results:

The mean (±standard deviation) 24-h intra-and postoperative opioid consumption showed no difference between the proximal and distal groups (39.72 ± 23.6 and 41.28 ± 19.6 mg IV morphine equivalents, respectively, P = 0.793). There was also no significant difference in the median [minimum, maximum] percentage change in TUG times relative to preoperative performance comparing proximal and distal ACB (334.0 [131, 1084] %-change and 458.5 [169, 1696] %-change, respectively, P = 0.130). In addition, there were no differences in postoperative pain scores or LOS.

Conclusions:

ACB performed at either proximal or distal locations shows no difference in postoperative pain measured by opioid consumption or pain scores. Better TUG performance seen in the proximal group was not statistically significant but might represent a clinically important difference in functional mobility.

The Use of Electrical Impedance to Identify Intraneural Needle Placement in Human Peripheral Nerves: A Study on Amputated Human Limbs

BACKGROUND

Even as the use of peripheral nerve blockade in the perioperative setting is increasing, neural injury secondary to accidental intraneural injection remains a significant patient safety concern. Current modalities, including electrical stimulation and ultrasound imaging, still lack consistency and absolute reliability in both the detection and prevention of this complication. The measurement of electrical impedance (EI) could be an easy and valuable additional tool to detect intraneural needle placement. Our objectives in this study were to measure the change in EI with intraneural needle advancement in recently amputated human limbs.

METHODS

The study was conducted within 45 minutes of amputation. The nerves that were studied were the sciatic nerve in the popliteal fossa in above-knee amputations or the tibial nerve below the calf in below-knee amputations. The amputated limb was placed on a tray and under ultrasound imaging guidance, an insulated peripheral block needle connected to a nerve stimulator was placed extraneurally and subsequently advanced intraneurally. The experiment was repeated on the same nerve after exposure by surgical dissection. The differences in impedance measurements between intraneural and extraneural needle placement were compared.

RESULTS

In the below-knee amputated extremity (tibial nerve, n = 6) specimens based on the ultrasound methods, mean ± SD for ultrasound-guided intraneural impedance was 10 ± 2 kΩ compared with an extraneural impedance of 6 ± 1.6 kΩ (P = 0.005). The difference between intraneural and extraneural impedance after open dissection was also significant when we repeated the analysis based on the same specimens (P = 0.005). Similarly, in the above-the-knee amputated extremity (sciatic nerve, n = 5) specimens, mean intraneural impedance was 35.2 ± 7.9 kΩ compared with an extraneural impedance of 25.2 ± 5.3 kΩ (P = 0.037). The difference between intraneural and extraneural impedance obtained after open dissection was also significant when we repeated the analysis based on the same specimens (P = 0.0002). The impedance values were consistent and similar to those obtained after open dissection.

CONCLUSIONS

There is no reliable "gold standard" to predict or prevent intraneural needle placement during peripheral nerve blockade. This small sample-sized study demonstrated that there is a change in EI with intraneural needle advancement. In clinical practice, measurement of the EI in conjunction with nerve stimulation may serve as another tool to use for identifying intraneural needle placement during peripheral nerve blockade.

Anticoagulation and Neuraxial/Peripheral Anesthesia

Novel anticoagulants (NAGs) have emerged as the preferred alternatives to vitamin K antagonists. In patients being considered for regional anesthesia, these drugs present a layer of complexity in the preprocedure evaluation. There are no established tests to monitor anticoagulant activity and our experience is short with these drugs. These authors believe it is important to review the relevant hematology, orthopedics, and anesthesiology literature to provide a valuable reference for the clinician who is met with these challenges. In addition to discussing NAGs, we also review the existing American Society of Regional Anesthesia guidelines for heparin, low-molecular-weight heparin, and antiplatelet agents.

Exparel/Peripheral Catheter Use in the Ambulatory Setting and Use of Peripheral Catheters Postoperatively in the Home Setting

PURPOSE OF REVIEW

With the increasing number of ambulatory surgeries being performed, regional anesthesia has become an increasingly popular anesthetic modality, and many choices exist to provide efficient, effective quality perioperative analgesia. In this paper, we will review the various regional anesthesia options in addition to the advantages and disadvantages of each. Lastly, we will discuss liposomal bupivicaine, a long acting local anesthetic, and its future role in the anesthesiologist's armamentarium. The aim of the publication is to provide a general overview of regional anesthesia as well as to discuss the advantages and disadvantages of this modality. Additionally, we sought to review the basics of liposomal bupivicaine as well as the relevant literature.

RECENT FINDINGS

The results regarding liposomal bupivicaine are mixed and mainly focuses on local infiltration and intra-articular injections. There are no known studies specifically comparing liposomal bupivicaine to bupivicaine hydrochloride in ultrasound-guided nerve blocks. There is some encouraging data regarding liposomal bupivicaine, but further studies are needed before it is adopted as a mainstay of treatment. In addition to efficacy, additional investigations are needed to evaluate cost as this could be a major impediment to its implementation.

Review of perioperative pain management of opioid-dependent patients

Opioid dependence can occur due to prescription opioid use, recreational opioid use, or as a result of opioid use for the treatment of drug addiction. Pain control in these patients is truly a challenge. It is important to understand the patient's condition such as the phenomenon of drug dependence, drug addiction, and pseudoaddiction to provide effective analgesia. This may be accomplished using appropriate multimodal therapies and by treatment of coexisting diseases such as anxiety. The goal is to provide effective analgesia, prevent cognitive and emotional problems, and produce a positive postoperative rehabilitation process. Multimodal options include pharmacological and nonpharmacological approaches, psychological support, and interventional pain procedures, all focused toward providing optimal pain control while preventing undertreatment, withdrawal symptoms, and other complications.

Intrathecal analgesia: time to consider it for your patient?

When systemic analgesics or antispasmodics fail to control chronic pain or cause intolerable adverse effects, an intrathecal drug delivery system may be the best bet.

Multimodal therapy in perioperative analgesia

This article reviews the current evidence for multimodal analgesic options for common surgical procedures. As perioperative physicians, we have come a long way from using only opioids for postoperative pain to combinations of acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), selective Cyclo-oxygenase (COX-2) inhibitors, local anesthetics, N-methyl-d-aspartate (NMDA) receptor antagonists, and regional anesthetics. As discussed in this article, many of these agents have decreased narcotic requirements, improved patient satisfaction, and decreased postanesthesia care unit (PACU) times, as well as morbidity in the perioperative period.

Timing of Neuraxial Pain Interventions Following Blood Patch for Post Dural Puncture Headache

Post dural puncture headache (PDPH) is a common complication of interventional neuraxial procedures. Larger needle gauge, younger patients, low body mass index, women (especially pregnant women), and “traumatic” needle types are all associated with a higher incidence of PDPH. Currently, an epidural blood patch is the gold-standard treatment for this complication. However, despite the high PDPH cure rate through the use of this therapy, little is known about the physiology behind the success of the epidural blood patch, specifically, the time course of patch formation within the epidural space or how long it takes for the blood patch volume to be resorbed by the body. Of the many unanswered and debated topics related to PDPH and epidural blood patches, one additional specific question that may alter clinical management is when it is safe for patients who have experienced a disruption of the thecal space and have undergone this procedure to have a subsequent epidural or spinal procedure, such as a neuraxial anesthetic (i.e. a spinal anesthetic for an elective outpatient procedure) or an interventional pain procedure for chronic pain management. This question becomes more unclear if the new procedure includes a steroid medication. As an example, an older patient presents with a history of lumbar disc disease and during lumbar epidural steroid injection, an inadvertent wet tap occurs leading to PDPH. Following management with fluids, caffeine, medications, and a successful epidural blood patch, it remains unclear as to when would be the best time frame to consider a second lumbar epidural steroid injection. We identified the 3 main risk factors of subsequent interventional neuraxial procedures as (1) disruption of the epidural blood patch and ongoing reparative processes, (2) epidural procedure failure, and (3) infection. We looked at the literature, and summarized the existing literature in order to enable health care professionals to understand the time course of dural repair as well as the risks of subsequent neuraxial procedures after epidural blood patches. This review poses the question using an evidence based review to discuss the appropriate time course to proceed. Key words: Post dural puncture headache, epidural steroid injection, wet tap, timing of therapy

Timing of neuraxial pain interventions following blood patch for post dural puncture headache

Post dural puncture headache (PDPH) is a common complication of interventional neuraxial procedures. Larger needle gauge, younger patients, low body mass index, women (especially pregnant women), and "traumatic" needle types are all associated with a higher incidence of PDPH. Currently, an epidural blood patch is the gold-standard treatment for this complication. However, despite the high PDPH cure rate through the use of this therapy, little is known about the physiology behind the success of the epidural blood patch, specifically, the time course of patch formation within the epidural space or how long it takes for the blood patch volume to be resorbed by the body. Of the many unanswered and debated topics related to PDPH and epidural blood patches, one additional specific question that may alter clinical management is when it is safe for patients who have experienced a disruption of the thecal space and have undergone this procedure to have a subsequent epidural or spinal procedure, such as a neuraxial anesthetic (i.e. a spinal anesthetic for an elective outpatient procedure) or an interventional pain procedure for chronic pain management. This question becomes more unclear if the new procedure includes a steroid medication. As an example, an older patient presents with a history of lumbar disc disease and during lumbar epidural steroid injection, an inadvertent wet tap occurs leading to PDPH. Following management with fluids, caffeine, medications, and a successful epidural blood patch, it remains unclear as to when would be the best time frame to consider a second lumbar epidural steroid injection. We identified the 3 main risk factors of subsequent interventional neuraxial procedures as (1) disruption of the epidural blood patch and ongoing reparative processes, (2) epidural procedure failure, and (3) infection. We looked at the literature, and summarized the existing literature in order to enable health care professionals to understand the time course of dural repair as well as the risks of subsequent neuraxial procedures after epidural blood patches. This review poses the question using an evidence based review to discuss the appropriate time course to proceed.

Resolution of Long Standing Tinnitus Following Radiofrequency Ablation of C2-C3 Medial Branches – A Case Report

Tinnitus is described as an auditory phantom perception analogous to central neuropathic pain. Despite the high prevalence of this debilitating symptom, no intervention is recognized that reliably eliminates tinnitus symptoms; a cause has yet to be determined. A 65-year-old healthy man presented with a 3 year history of left-sided tinnitus. Full workup performed by the primary care physician including blood tests for electrolyte imbalance, consultations by 2 independent otholaryngologists, and imaging did not reveal abnormalities to provide etiology of the tinnitus. No other complaints were noted except for occasional minimal left sided neck pain. Cervical spine x-ray showed degenerative changes with facet hypertrophy more pronounced on the left side. Subsequently, the patient underwent diagnostic left-sided C2-C3 medial branch block, resulting in complete resolution of tinnitus for more than 6 hours. After successful radiofrequency ablation of left C2-C3 medial branches, the patient became asymptomatic. At one year follow-up, he continued to be symptom free. Sparce studies have shown interaction between the somatosensory and auditory system at dorsal cochlear nucleus (DCN), inferior colliculus, and parietal association areas. Upper cervical nerve (C2) electrical stimulation evokes potentials in the DCN, eliciting strong patterns of inhibition and weak excitation of the DCN principal cells. New evidence demonstrated successful transcutaneous electrical nerve stimulation (TENS) of upper cervical nerve (C2) for treatment of somatic tinnitus in 240 patients. This case indicates that C2-C3 facet arthropathy may cause tinnitus and radiofrequency ablation of C2-C3 medial branches can provide an effective approach not previously considered. Key words: Radiofrequency ablation, tinnitus, neuropathic pain, cervical medial branch block, cervical pain, auditory phantom perception

Resolution of long standing tinnitus following radiofrequency ablation of C2-C3 medial branches--a case report

Tinnitus is described as an auditory phantom perception analogous to central neuropathic pain. Despite the high prevalence of this debilitating symptom, no intervention is recognized that reliably eliminates tinnitus symptoms; a cause has yet to be determined. A 65-year-old healthy man presented with a 3 year history of left-sided tinnitus. Full workup performed by the primary care physician including blood tests for electrolyte imbalance, consultations by 2 independent otholaryngologists, and imaging did not reveal abnormalities to provide etiology of the tinnitus. No other complaints were noted except for occasional minimal left sided neck pain. Cervical spine x-ray showed degenerative changes with facet hypertrophy more pronounced on the left side. Subsequently, the patient underwent diagnostic left-sided C2-C3 medial branch block, resulting in complete resolution of tinnitus for more than 6 hours. After successful radiofrequency ablation of left C2-C3 medial branches, the patient became asymptomatic. At one year follow-up, he continued to be symptom free. Sparce studies have shown interaction between the somatosensory and auditory system at dorsal cochlear nucleus (DCN), inferior colliculus, and parietal association areas. Upper cervical nerve (C2) electrical stimulation evokes potentials in the DCN, eliciting strong patterns of inhibition and weak excitation of the DCN principal cells. New evidence demonstrated successful transcutaneous electrical nerve stimulation (TENS) of upper cervical nerve (C2) for treatment of somatic tinnitus in 240 patients. This case indicates that C2-C3 facet arthropathy may cause tinnitus and radiofrequency ablation of C2-C3 medial branches can provide an effective approach not previously considered.

Meningitis or epidural abscesses after neuraxial block for removal of infected hip or knee prostheses

BACKGROUND

Infection, whether localized or systemic, can be a relative contraindication to neuraxial anaesthesia. Data correlating neuraxial anaesthesia and the development of meningitis or epidural abscess in this setting are limited.

METHODS

Retrospective chart review was performed on 710 medical records of patients admitted between 1998 and 2009 for removal of potentially infected total hip and total knee prostheses. Ultimately, 474 patients were identified as being infected. Factors that predisposed a patient to an immunocompromised state, and signs and symptoms of infection in the pre-, intra-, and postoperative stages were documented. Bacteraemic patients were reviewed for signs of neuraxial infection. The endpoint of follow-up was development of complications before hospital discharge.

RESULTS

All 474 patients had removal of the infected prosthesis under neuraxial anaesthesia. Mean patient age was 65.5 yr (58% >65 yr) and mean length of hospital stay was 21 days. Patient characteristics included concurrent disease (65%), steroid use (5.3%), preoperative antibiotic use (50.8%), signs of inflammatory process (84%), bacteraemia (4.2%), and documented positive intraoperative joint cultures (88%). Using clinical standards for diagnosis of central neuraxial infection, patients developed infectious complications (incidence of 0.6% on 95% confidence interval), although three patients had findings attributable to anaesthesia, including epidural haematoma, psoas abscess, and back pain.

CONCLUSIONS

Based on clinical criteria, our findings suggest that the incidence of central nervous system infection after neuraxial anaesthesia in patients with infected hip and knee prostheses is low after neuraxial block.